Catalytic reforming, refining process

For the refiner, the reduction in benzene concentration to 3% is not a major problem it is achieved by adjusting the initial point of the feed to the catalytic reformers and thereby limiting the amount of benzene precursors such as cyclohexane and Cg paraffins. Further than 3% benzene, the constraints become very severe and can even imply using specific processes alkylation of benzene to substituted aromatics, separation, etc. 

Catalytic cracking is a key refining process along with catalytic reforming and alkylation for the production of gasoline. Operating at low pressure and in the gas phase, it uses the catalyst as a solid heat transfer medium. The reaction temperature is 500-540°C and residence time is on the order of one second. 

Simple conventional refining is based essentially on atmospheric distillation. The residue from the distillation constitutes heavy fuel, the quantity and qualities of which are mainly determined by the crude feedstock available without many ways to improve it. Manufacture of products like asphalt and lubricant bases requires supplementary operations, in particular separation operations and is possible only with a relatively narrow selection of crudes (crudes for lube oils, crudes for asphalts). The distillates are not normally directly usable processing must be done to improve them, either mild treatment such as hydrodesulfurization of middle distillates at low pressure, or deep treatment usually with partial conversion such as catalytic reforming. The conventional refinery thereby has rather limited flexibility and makes products the quality of which is closely linked to the nature of the crude oil used. 

Any chemical derived from petroleum, the main refining processes being fractional distillation, catalytic cracking and platforming (reforming the constituents with the aid of a platinum catalyst). Since sulphur may be recovered from petroleum refining and since SBR, furnace black and processing oils are all petrochemicals it is... 

Catforming [Catalytic reforming] A catalytic reforming process using a platinum catalyst on a silica/alumina support. Developed by the Atlantic Refining Company and first operated in 1952. 

Cycloversion A petroleum treatment process which combined catalytic reforming with hydrodesulfurization. The catalyst was bauxite. The process differed from the Houdry process in that the catalyst bed temperature was controlled by injecting an inert gas. Developed by the Phillips Petroleum Company and used in the United States in the 1940s. Pet. Refin., 1960, 39(9), 205. 

The modem gasolines are produced by blending products from cmde oil distillation, that is, fluid catalytic cracking, hydrocraking, reforming, coking, polymerization, isomerization, and alkylation.Two clear examples of the possible use of solid-acid catalysts in refining processes are the isomerization of lineal alkanes and the alkylation of isobutene with butanes. In both these cases, and due to the octane... 

The separation of organic mixtures into groups of components of similar chemical type was one of the earliest applications of solvent extraction. In this chapter the term solvent is used to define the extractant phase that may contain either an extractant in a diluent or an organic compound that can itself act as an extractant. Using this technique, a solvent that preferentially dissolves aromatic compounds can be used to remove aromatics from kerosene to produce a better quality fuel. In the same way, solvent extraction can be used to produce high-purity aromatic extracts from catalytic reformates, aromatics that are essentially raw materials in the production of products such as polystyrene, nylon, and Terylene. These features have made solvent extraction a standard technique in the oil-refining and petrochemical industries. The extraction of organic compounds, however, is not confined to these industries. Other examples in this chapter include the production of pharmaceuticals and environmental processes. 

Fixed- or packed-bed reactors refer to two-phase systems in which the reacting fluid flows through a tube filled with stationary catalyst particles or pellets (Smith, 1981). As in the case of ion-exchange and adsorption processes, fixed bed is the most frequently used operation for catalysis (Froment and Bischoff, 1990 Schmidt, 2005). Some examples in the chemical industry are steam reforming, the synthesis of sulfuric acid, ammonia, and methanol, and petroleum refining processes such as catalytic reforming, isomerization, and hydrocracking (Froment and Bischoff, 1990). 

In a catalytic de-alkylation process, toluene or Q aromatics (alkylben-zenes) are fed to a reactor, together with a hydrogen-containing gas. See Fig. 1. The hydrogen source is not critical and may be manufactured hydrogen or off-gas from a reforming or other refining unit. Effluent from the... 

Well over 50 large-scale EO model-based RTO applications have been deployed for petroleum refining processes. These model applications have been deployed in petroleum refineries Liporace et al., 2009 Camolesi et al., 2008 Mudt et al., 1995, both on separation units (crude atmospheric and vacuum distillation units) and on reactor units (including fluidized catalytic crackers (FCC), gasoline reformers, and hydrocrackers). 

Once the synthetic crude oils from coal and oil shale have been upgraded and the heavy ends converted to lighter distillates, further refining by existing processes need not be covered in detail except to note the essential character of the products. The paraffinic syncrude from oil shale yields middle distillates which are excellent jet and diesel fuel stocks. The principal requirements are removal of nitrogen to the extent necessary for good thermal stability of the fuels and adjustment of cut points to meet required pour or freeze points, limited by the presence of waxy straight-chain paraffins. The heavy naphtha from shale oil can be further hydrotreated and catalytically reformed to acceptable octane number, but with considerable loss of volume because of the only moderate content of cyclic hydrocarbons, typically 45-50%. On the other... 

Fig. 18.17. Catalytic reforming—Axens. Includes moving-bed reactors (1,2,3) and regenerator (4). (Source Hydrocarbon Processing, 2004 Refining Process Handbook. CD-ROM. September 2004 copyright Gulf Publishing Co., all rights reserved.)...

---